Merge branch '2.1.x' into 2.2.x

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -595,12 +595,13 @@ class JarFileTests {
 			jarOutputStream.write(new byte[] { (byte) 1 });
 			jarOutputStream.closeEntry();
 		}
-		JarFile jarFile = new JarFile(file);
-		Enumeration<java.util.jar.JarEntry> entries = jarFile.entries();
+		try (JarFile jar = new JarFile(file)) {
+			Enumeration<java.util.jar.JarEntry> entries = jar.entries();
 			JarEntry entry = entries.nextElement();
 			assertThat(entry.getLastModifiedTime().toInstant()).isEqualTo(Instant.EPOCH);
 			assertThat(entry.getName()).isEqualTo("1.dat");
 		}
+	}
 
 	private int getJavaVersion() {
 		try {